In the treatment of hyperphosphatemia, calcium preparations are in broad use today.
Calcium preparations have the drawback that they induce hypercalcemia to promote ectopic calcification, which imposes limits on their dosage. As an additional disadvantage, those preparations inhibit absorption of iron to encourage progression of renal anemia.
In the medical scene, a drug which is free from these defect and effective for the treatment of hyperphosphatemia is demanded, and this invention has for its object to fulfill this need.